This Shared Instrumentation Grant proposal requests funds to purchase a Zeiss LSM 510 NLO multiphoton laser scanning microscope, to be installed in the Bio-Optics Laboratory at the University of Oregon. This microscope will be used to advance ongoing NIH supported research in numerous laboratories in the Institutes of Neuroscience and Molecular Biology at the University of Oregon, including six major users who have described specific projects that will be greatly facilitated by the availability of a multi-photon fluorescence microscope. The two main benefits offered by this new technology are (1) the capability performing time-lapse microscopy on living specimens with greatly reduced photodynamic damage or bleaching of fluorescent labels and (2) the ability to obtain crisp images at depths of 100 mu m or more into a specimen. Five of the major users study the developmental biology of zebrafish (Judith Eisen, Charles Kimmel and John Postlethwait), Drosophila (Chris Doe), tunicates (John Postlethwait) and C. elegans (Bruce Bowerman). One user (William Roberts) studies synaptic physiology and calcium signaling in sensory receptors in the frog ear. The microscope will be available as a shared facility for use by life scientists at the University of Oregon.